diff --git a/src/scgenerator/evaluator.py b/src/scgenerator/evaluator.py
index 11fd3ae..3349e34 100644
--- a/src/scgenerator/evaluator.py
+++ b/src/scgenerator/evaluator.py
@@ -459,8 +459,8 @@ default_rules: list[Rule] = [
         "dynamic_dispersion",
         lambda pressure: isinstance(pressure, (list, tuple, np.ndarray)),
     ),
-    Rule("w0", units.m, ["wavelength"]),
-    Rule("l", units.m.inv, ["w"]),
+    Rule("w0", units.m_rads, ["wavelength"]),
+    Rule("l", units.m_rads, ["w"]),
     Rule("w0_ind", math.argclosest, ["w_for_disp", "w0"]),
     Rule("w_num", len, ["w"]),
     Rule("dw", lambda w: w[1] - w[0]),
@@ -490,7 +490,7 @@ default_rules: list[Rule] = [
     Rule("soliton_length", pulse.soliton_length),
     Rule("c_to_a_factor", lambda: 1, priorities=-1),
     # Fiber Dispersion
-    Rule("w_for_disp", units.m, ["wl_for_disp"]),
+    Rule("w_for_disp", units.m_rads, ["wl_for_disp"]),
     Rule("gas_info", materials.Gas),
     Rule("chi_gas", lambda gas_info, wl_for_disp: gas_info.sellmeier.chi(wl_for_disp)),
     Rule("n_gas_2", materials.n_gas_2),
diff --git a/src/scgenerator/helpers.py b/src/scgenerator/helpers.py
index 6d91382..cfb1359 100644
--- a/src/scgenerator/helpers.py
+++ b/src/scgenerator/helpers.py
@@ -1,30 +1,30 @@
 """
 series of helper functions
 """
-
-from contextlib import nullcontext
+import warnings
 from pathlib import Path
-from typing import Any, Mapping
 
+import matplotlib.pyplot as plt
 import numpy as np
-import tomli
 
-from scgenerator.math import all_zeros
+from scgenerator.math import abs2, all_zeros
 from scgenerator.parameter import Parameters
 from scgenerator.physics.fiber import beta2, n_eff_hasan, n_eff_marcatili
 from scgenerator.physics.materials import n_gas_2
-from scgenerator.physics.units import c, nm
+from scgenerator.physics.units import c, nm_rads
+from scgenerator.solver import solve43
+from scgenerator.spectra import Propagation, propagation
 
 try:
     from tqdm import tqdm
 except ModuleNotFoundError:
     tqdm = None
 
-__all__ = ["capillary_dispersion", "capillary_zdw", "revolver_dispersion", "quick_sim", "w_from_wl"]
+__all__ = ["capillary_dispersion", "capillary_zdw", "revolver_dispersion", "compute", "w_from_wl"]
 
 
 def w_from_wl(wl_min_nm: float, wl_max_nm: float, n: int) -> np.ndarray:
-    return np.linspace(nm(wl_max_nm), nm(wl_min_nm), n)
+    return np.linspace(nm_rads(wl_max_nm), nm_rads(wl_min_nm), n)
 
 
 def capillary_dispersion(
@@ -162,40 +162,29 @@ def extend_axis(axis: np.ndarray) -> np.ndarray:
     return axis
 
 
-def quick_sim(params: dict[str, Any] | Parameters, **_params: Any) -> tuple[Parameters, np.ndarray]:
-    """
-    run a quick simulation
+def compute(parameters: Parameters, overwrite: bool = False) -> Propagation:
+    name = Path(parameters.compute("name")).stem + ".zip"
 
-    Parameters
-    ----------
-    params : dict[str, Any] | Parameters | os.PathLike
-        a dict of parameters, a Parameters obj or a path to a toml file from which to read the
-        parameters
-    _params : Any
-        override the initial parameters with these keyword arguments
+    prop_params = parameters.compile()
+    prop = propagation(name, prop_params, bundle_data=True, overwrite=overwrite)
 
-    Example
-    -------
-    ```
-    params, sim = quick_sim("long_fiber.toml", energy=10e-6)
-    ```
-
-    """
-    if isinstance(params, Mapping):
-        params = Parameters(**(params | _params))
-    else:
-        params = Parameters(**(tomli.loads(Path(params).read_text()) | _params))
-
-    sim = RK4IP(params)
-    if tqdm:
-        pbar = tqdm(total=params.z_num)
-
-        def callback(_, __):
+    with warnings.catch_warnings(), tqdm(total=prop_params.z_num) as pbar:
+        warnings.filterwarnings("error")
+        for i, (spec, new_stat) in enumerate(
+            solve43(
+                prop_params.spec_0,
+                prop_params.linear_operator,
+                prop_params.nonlinear_operator,
+                prop_params.length,
+                prop_params.tolerated_error,
+                prop_params.tolerated_error,
+                0.9,
+                targets=prop_params.z_targets,
+            )
+        ):
             pbar.update()
+            plt.plot(prop_params.t, abs2(prop_params.ifft(spec)))
+            plt.show()
+            prop.append(spec)
 
-    else:
-        pbar = nullcontext()
-        callback = None
-
-    with pbar:
-        return params, sim.run(progress_callback=callback)
+    return prop
diff --git a/src/scgenerator/math.py b/src/scgenerator/math.py
index 1c542b1..8072d77 100644
--- a/src/scgenerator/math.py
+++ b/src/scgenerator/math.py
@@ -40,7 +40,7 @@ def total_extent(*vec: np.ndarray) -> float:
 
 def span_above(arr: np.ndarray, threshold: float) -> tuple[int, int]:
     """returns the first and last index where the array is above the specified threshold"""
-    ind = np.where(arr >= threshold)[0]
+    ind = np.where(arr >= threshold)[-1]
     return np.min(ind), np.max(ind)
 
 
diff --git a/src/scgenerator/noise.py b/src/scgenerator/noise.py
index a81b635..f5bfa56 100644
--- a/src/scgenerator/noise.py
+++ b/src/scgenerator/noise.py
@@ -228,4 +228,4 @@ def segments(signal: np.ndarray, num_segments: int) -> np.ndarray:
 
 
 def quantum_noise_limit(wavelength: float, power: float) -> float:
-    return units.m(wavelength) * units.hbar * 2 / power
+    return units.m_rads(wavelength) * units.hbar * 2 / power
diff --git a/src/scgenerator/physics/__init__.py b/src/scgenerator/physics/__init__.py
index 40b99a5..3551ca3 100644
--- a/src/scgenerator/physics/__init__.py
+++ b/src/scgenerator/physics/__init__.py
@@ -15,7 +15,7 @@ T = TypeVar("T")
 
 
 def group_delay_to_gdd(wavelength: np.ndarray, group_delay: np.ndarray) -> np.ndarray:
-    w = units.m.inv(wavelength)
+    w = units.m_rads(wavelength)
     gdd = np.gradient(group_delay, w)
     return gdd
 
@@ -48,7 +48,7 @@ def material_dispersion(
         beta2 as function of wavelength
     """
 
-    w = units.m(wavelengths)
+    w = units.m_rads(wavelengths)
 
     sellmeier = materials.Sellmeier.load(material)
     n_gas_2 = sellmeier.n_gas_2(wavelengths, temperature, pressure)
@@ -84,7 +84,7 @@ def find_optimal_depth(
     w = w_c + w0
     disp = np.zeros(len(w))
     ind = w > (w0 / 10)
-    disp[ind] = material_dispersion(units.m.inv(w[ind]), material)
+    disp[ind] = material_dispersion(units.m_rads(w[ind]), material)
 
     def propagate(z):
         return spectrum * np.exp(-0.5j * disp * w_c**2 * z)
@@ -124,6 +124,6 @@ def propagate_field(
         propagated field
     """
     w_c = math.wspace(t)
-    l = units.m(w_c + units.nm(center_wl_nm))
+    l = units.m_rads(w_c + units.nm_rads(center_wl_nm))
     disp = material_dispersion(l, material)
     return np.fft.ifft(np.fft.fft(field) * np.exp(0.5j * disp * w_c**2 * z))
diff --git a/src/scgenerator/physics/fiber.py b/src/scgenerator/physics/fiber.py
index 548f6ec..c31b2d4 100644
--- a/src/scgenerator/physics/fiber.py
+++ b/src/scgenerator/physics/fiber.py
@@ -141,7 +141,7 @@ def plasma_dispersion(wl_for_disp, number_density, simple=False):
     """
 
     e2_me_e0 = 3182.60735  # e^2 /(m_e * epsilon_0)
-    w = units.m(wl_for_disp)
+    w = units.m_rads(wl_for_disp)
     if simple:
         w_pl = number_density * e2_me_e0
         return -(w_pl**2) / (c * w**2)
@@ -544,7 +544,7 @@ def HCPCF_dispersion(
         beta2 as function of wavelength
     """
 
-    w = units.m(wl_for_disp)
+    w = units.m_rads(wl_for_disp)
     n_gas_2 = mat.Sellmeier.load(gas_name).n_gas_2(wl_for_disp, temperature, pressure)
 
     n_eff_func = dict(
diff --git a/src/scgenerator/physics/materials.py b/src/scgenerator/physics/materials.py
index 588b0e8..2ebf4f9 100644
--- a/src/scgenerator/physics/materials.py
+++ b/src/scgenerator/physics/materials.py
@@ -358,7 +358,7 @@ def delta_gas(w: np.ndarray, gas: Gas) -> np.ndarray:
         delta_t
         since 2 gradients are computed, it is recommended to exclude the 2 extremum values
     """
-    chi = gas.sellmeier.chi(units.m.inv(w))
+    chi = gas.sellmeier.chi(units.m_rads(w))
     N0 = gas.number_density_van_der_waals()
 
     dchi_dw = np.gradient(chi, w)
diff --git a/src/scgenerator/physics/pulse.py b/src/scgenerator/physics/pulse.py
index 13a90d7..482e078 100644
--- a/src/scgenerator/physics/pulse.py
+++ b/src/scgenerator/physics/pulse.py
@@ -468,7 +468,7 @@ def correct_wavelength(init_wavelength: float, w_c: np.ndarray, field_0: np.ndar
     to field_0 is located at init_wavelength
     """
     delta_w = w_c[np.argmax(math.abs2(np.fft.fft(field_0)))]
-    return units.m.inv(units.m(init_wavelength) - delta_w)
+    return units.m_rads(units.m_rads(init_wavelength) - delta_w)
 
 
 def E0_to_P0(energy: float, t0: float, shape: str):
diff --git a/src/scgenerator/physics/units.py b/src/scgenerator/physics/units.py
index 19ddb61..612c759 100644
--- a/src/scgenerator/physics/units.py
+++ b/src/scgenerator/physics/units.py
@@ -30,7 +30,7 @@ types are "WL", "FREQ", "AFREQ", "TIME", "PRESSURE", "TEMPERATURE", "OTHER"
 """
 _T = TypeVar("_T")
 _UT = Callable[[_T], _T]
-PRIMARIES = dict(WL="Rad/s", FREQ="Rad/s", AFREQ="Rad/s", TIME="s", PRESSURE="Pa", TEMPERATURE="K")
+PRIMARIES = dict(WL="m", FREQ="Rad/s", AFREQ="Rad/s", TIME="s", PRESSURE="Pa", TEMPERATURE="K")
 
 
 class UnitMap(dict):
@@ -128,17 +128,27 @@ class unit:
 
 @unit("WL", r"Wavelength λ (m)")
 def m(l: _T) -> _T:
-    return 2 * pi * c / l
+    return l
 
 
 @unit("WL", r"Wavelength λ (nm)")
 def nm(l: _T) -> _T:
-    return 2 * pi * c / (l * 1e-9)
+    return l * 1e-9
+
+
+@nm.inverse
+def nm_inv(l: _T) -> _T:
+    return l * 1e9
 
 
 @unit("WL", r"Wavelength λ (μm)")
 def um(l: _T) -> _T:
-    return 2 * pi * c / (l * 1e-6)
+    return l * 1e-6
+
+
+@nm.inverse
+def um_inv(l: _T) -> _T:
+    return l * 1e6
 
 
 @unit("FREQ", r"Frequency $f$ (Hz)")
@@ -321,6 +331,18 @@ def no_unit(x: _T) -> _T:
     return x
 
 
+def nm_rads(nm: _T) -> _T:
+    return 2e9 * np.pi * c / nm
+
+
+def um_rads(um: _T) -> _T:
+    return 2e6 * np.pi * c / um
+
+
+def m_rads(m: _T) -> _T:
+    return 2 * np.pi * c / m
+
+
 def get_unit(unit: Union[str, Callable]) -> Callable[[float], float]:
     if isinstance(unit, str):
         return units_map[unit]
diff --git a/src/scgenerator/plotting.py b/src/scgenerator/plotting.py
index a72538b..2407319 100644
--- a/src/scgenerator/plotting.py
+++ b/src/scgenerator/plotting.py
@@ -433,8 +433,8 @@ def plot_2D(
 def transform_2D_propagation(
     values: np.ndarray,
     plt_range: Union[PlotRange, RangeType],
-    x_axis: np.ndarray = None,
-    y_axis: np.ndarray = None,
+    x_axis: np.ndarray,
+    y_axis: np.ndarray,
     log: Union[int, float, bool, str] = "1D",
 ) -> tuple[np.ndarray, np.ndarray, np.ndarray]:
     """
@@ -470,10 +470,8 @@ def transform_2D_propagation(
     if values.ndim != 2:
         raise ValueError(f"shape was {values.shape}. Can only plot 2D array")
     is_complex, plt_range = prep_plot_axis(values, plt_range)
-    if is_complex or any(values.ravel() < 0):
+    if is_complex or np.any(values < 0):
         values = abs2(values)
-    # if params.full_field and plt_range.unit.type == "TIME":
-    #     values = envelope_2d(x_axis, values)
 
     x_axis, values = uniform_axis(x_axis, values, plt_range)
     y_axis, values.T[:] = uniform_axis(y_axis, values.T, None)
@@ -792,7 +790,7 @@ def transform_1D_values(
     new_axis, ind, ext = sort_axis(x_axis, plt_range)
     values = values[ind]
     if plt_range.unit.type == "WL" and plt_range.conserved_quantity:
-        values = units.to_WL(values, units.m.inv(plt_range.unit(new_axis)))
+        values = units.to_WL(values, units.m_rads(plt_range.unit(new_axis)))
 
     if isinstance(spacing, (float, np.floating)):
         tmp_axis = np.linspace(*span(new_axis), int(len(new_axis) / spacing))
@@ -1006,7 +1004,7 @@ def apply_log(values: np.ndarray, log: Union[str, bool, float, int]) -> np.ndarr
         elif log == "2D":
             values = math.to_dB(values, ref=values.max())
         elif log == "1D" or log is True:
-            values = np.apply_along_axis(math.to_dB, -1, values)
+            values = math.to_dB(values)
         elif log == "smooth 1D":
             ref = np.max(values, axis=1)
             ind = np.argmax((ref[:-1] - ref[1:]) < 0)
@@ -1160,10 +1158,14 @@ def summary_plot(
     wl_range: PlotRange | None = None,
     t_range: PlotRange | None = None,
     db_min: float = -50.0,
+    axes: tuple[Axes, Axes] | None = None,
 ):
     wl_int = specs.wl_int
     time_int = specs.time_int
 
+    if z is None:
+        z = np.arange(specs.shape[0])
+
     if wl_range is None:
         imin, imax = math.span_above(wl_int, wl_int.max() * 1e-6)
         wl_range = PlotRange(specs.wl_disp[imin] * 1e9, specs.wl_disp[imax] * 1e9, "nm")
@@ -1172,5 +1174,13 @@ def summary_plot(
         imin, imax = math.span_above(time_int, time_int.max() * 1e-6)
         t_range = PlotRange(specs.t[imin] * 1e15, specs.t[imax] * 1e15, "fs")
 
-    fig, (left, right) = plt.subplots(1, 2)
-    transform_2D_propagation(wl_int, wl_range, specs.w, z)
+    if axes is None:
+        _, (left, right) = plt.subplots(1, 2)
+    else:
+        left, right = axes
+
+    x, y, values = transform_2D_propagation(wl_int, wl_range, specs.wl_disp, z, log="1D")
+    left.imshow(values, extent=get_extent(x, y), origin="lower", aspect="auto", vmin=db_min)
+
+    x, y, values = transform_2D_propagation(time_int, t_range, specs.t, z, log=False)
+    right.imshow(values, extent=get_extent(x, y), origin="lower", aspect="auto", vmin=db_min)
diff --git a/src/scgenerator/spectra.py b/src/scgenerator/spectra.py
index 61e0d61..f044761 100644
--- a/src/scgenerator/spectra.py
+++ b/src/scgenerator/spectra.py
@@ -47,7 +47,7 @@ class Spectrum(np.ndarray):
         # We first cast to be our class type
         obj = np.asarray(input_array).view(cls)
         # add the new attribute to the created instance
-        obj.order = np.argsort(w)
+        obj.w_order = np.argsort(w)
         obj.w = w
         if t is not None:
             obj.t = t
@@ -55,6 +55,7 @@ class Spectrum(np.ndarray):
             obj.t = math.iwspace(obj.w)
         obj.ifft = ifft
         obj.l = 2 * np.pi * units.c / obj.w
+        obj.l_order = np.argsort(obj.l)
 
         if not (len(obj.w) == len(obj.t) == len(obj.l) == obj.shape[-1]):
             raise ValueError(
@@ -72,7 +73,8 @@ class Spectrum(np.ndarray):
         self.w = getattr(obj, "w", None)
         self.t = getattr(obj, "t", None)
         self.l = getattr(obj, "l", None)
-        self.order = getattr(obj, "order", None)
+        self.w_order = getattr(obj, "w_order", None)
+        self.l_order = getattr(obj, "l_order", None)
         self.ifft = getattr(obj, "ifft", None)
 
     def __getitem__(self, key) -> "Spectrum":
@@ -80,15 +82,15 @@ class Spectrum(np.ndarray):
 
     @property
     def wl_disp(self):
-        return self.l[self.order][::-1]
+        return self.l[self.l_order]
 
     @property
     def w_disp(self):
-        return self.w[self.order]
+        return self.w[self.w_order]
 
     @property
     def wl_int(self):
-        return units.to_WL(math.abs2(self), self.l)[self.order][::-1]
+        return units.to_WL(math.abs2(self), self.l)[..., self.l_order]
 
     @property
     def freq_int(self):
@@ -113,15 +115,15 @@ class Spectrum(np.ndarray):
             )
             * self
             / np.abs(self)
-            )[self.order][::-1]
+        )[..., self.l_order]
 
     @property
     def freq_amp(self):
-        return self[self.order]
+        return self[..., self.w_order[::-1]]
 
     @property
     def afreq_amp(self):
-        return self[self.order]
+        return self[..., self.w_order[::-1]]
 
     @property
     def time_amp(self):
diff --git a/tests/test_evaluator.py b/tests/test_evaluator.py
index d665f5e..f88f1a0 100644
--- a/tests/test_evaluator.py
+++ b/tests/test_evaluator.py
@@ -33,7 +33,7 @@ def test_simple():
     evaluator.set(wavelength=800e-9, t_num=1024, dt=5e-15)
 
     assert evaluator.compute("t") == pytest.approx(math.tspace(t_num=1024, dt=5e-15))
-    assert evaluator.compute("w0") == pytest.approx(units.nm(800))
+    assert evaluator.compute("w0") == pytest.approx(units.nm_rads(800))
 
 
 def test_default_args_simple():
diff --git a/tests/test_grid.py b/tests/test_grid.py
index 3980b2f..64305d6 100644
--- a/tests/test_grid.py
+++ b/tests/test_grid.py
@@ -17,7 +17,7 @@ def test_scaling():
 def test_wl_dispersion():
     t = sc.tspace(t_num=1 << 15, dt=3.8e-15)
     w = sc.wspace(t)
-    wl = sc.units.m.inv(w + sc.units.nm(1546))
+    wl = sc.units.nm_rads(w + sc.units.nm_rads(1546)) * 1e-9
     wl_disp, ind_disp = sc.fiber.lambda_for_envelope_dispersion(wl, (950e-9, 4000e-9))
     assert all(np.diff(wl_disp) > 0)